Looking for an old phone number? Delpher.nl will help you out.
All telephone books from 1901 to 1950 have been imported into the “Books Basic” section of Delpher. Rather than entering a search term, click on search (magnifying glass) and filter the results (on the left-hand side of the screen) by “Origin”: Museum of Communication and possibly sort by date. Click here to have this action performed automatically.
You can also specify ‘telefoondienst’ in the “Title” field of the Advanced Search menu to get a list of phone books. You can find earlier results by searching for “telephoondienst”. Unfortunately, the database does not contain phone books for all years.
You can use the PROX operator in your search (searches for two words that are in close proximity, up to 10 words apart) in order to combine a name with a full or abbreviated street name or profession. Because certain names are very common, searching in phone books is different from searching regular books. People will, for example, often want to search for a name within a certain city, which will require browsing through quite some pages to get to the intended result. Browsing is often easier if you download the phone book as a PDF file first by clicking on the downward arrow.